Dry skin, the food you give him. I have a yellow female lab. She has dry skin and sheds a lot too. I changed her diet to a grain free diet with omega 3 pills to help with her coat. Since she has been on this she sheds less.
What's Causing My Labrador To Shed So Much Hair?
It could be his diet or he may have worms check with your local vet and see what he recommends